Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
An image forming apparatus such as a copier, a facsimile, and a printer includes an image forming unit, a transfer unit, and a fixing device. The image forming unit forms images on an image carrier (such as a photoreceptor drum). The transfer unit causes a toner image on the image carrier to be transferred onto a paper sheet as one example of a recording medium. The fixing device causes the toner images transferred onto the paper sheet to undergo heat fixing on the paper sheet.
As a fixing device, there is known a fixing device in which an electromagnetic induction heating (IH) method, which is capable of rapid heating and high efficiency heating, is employed. In the electromagnetic induction heating method, an induced current is induced on a fixing roller and a fixing belt due to magnetic flux generated by a high frequency current being flowed in an induction coil, thus heating the fixing roller and the fixing belt by Joule heat (induction heating). This Joule heat fixes the toner image on the paper sheet (recording medium).
In a fixing device of the electromagnetic induction heating method, there is known a technique that suppresses excessive temperature rise in a fixing belt and a fixing roller. This fixing device includes an inlet, to which airflow flows in, to cool an induction heating unit. Further, partial adjustment of a size of the inlet actively cools a high temperature region in the induction heating unit.